Astronomers Creep Up to the Edge of the Milky Way’s Black Hole | Quanta Magazine

Hot spots have been discovered orbiting just outside the supermassive black hole at the galaxy’s center. Their motions have given us the closest look at that violent environment.

“It’s a remarkable moment, in terms of these experiments’ ability to start probing how gravity works near a supermassive black hole,” Ghez said.

But since last year, the European team has had a unique tool—the power of four giant telescopes working together in a project called GRAVITY. On a typical night, the European Southern Observatory’s four 8-meter telescopes on Cerro Paranal, overlooking Chile’s Atacama desert, loll in different directions on the sky. GRAVITY pulls them together using a technique called interferometry that combines observations from multiple telescopes to produce artificial images that only a preposterously huge real telescope could make.